Wireless, radio frequency communication systems enable people to communicate with one another over long distances without having to access landline-connected devices such as conventional telephones. While early systems were primarily configured for voice communications, technological improvements have enabled the development of “3-G” (third generation) and similar wireless networks for both voice and high-speed packet data transfer. For example, CDMA-based, “1x-EVDO” (Evolution Data Optimized, or Evolution Data Only) wireless communication networks, now implemented in many parts of the U.S. and elsewhere, use the CDMA2000® 3-G mobile telecommunications protocol/specification for the high-speed wireless transmission of both voice and non-voice data. 1x-EVDO is an implementation of CDMA2000® that supports high data rates, specifically, forward link data rates up to 3.1 Mbit/s, and reverse link rates up to 1.8 Mbit/s in a radio channel dedicated to carrying high-speed packet data, e.g., a 1.25 MHz-bandwidth (or greater) radio channel separate from the radio channel for carrying voice data.
In 3-G packet data networks, e.g., those using the Internet Protocol (“IP”) for data transmission generally and voice over IP (“VoIP”) for voice-data transmission, data is broken into a plurality of addressed data packets. For example, with VoIP, analog audio/voice signals are captured, digitized, and broken into data packets. The data packets, both voice and non-voice, are then transmitted and routed over an IP-based communications network, where they are received and reassembled by the access terminal to which the data packets are addressed. Unlike circuit switched systems, however, in which a physical or logical circuit (e.g., pathway) is established for each call (with the resources for the circuit being dedicated to the call during the entirety of its duration), the data packets may be sent at different times, out of order, and/or along different pathways. In this manner, data transmission resources are utilized in a more efficient and optimized manner.
The use of VoIP allows voice services to be integrated with multimedia and other packet data services in a wireless communication network. This facilitates a diversity of applications, and may increase overall system performance. However, wireless networks present a particular challenge to packet voice traffic. Generally speaking, as network load increases, there is an increased likelihood of dropped calls, poor quality calls (e.g., resulting from increased frame error rates), long transmission latencies, and the like, all of which may lead to unacceptable levels of user dissatisfaction. More specifically, the air interface in a wireless network (e.g., the radio link between one or more fixed base stations and various mobile or other wireless access terminals) is dynamic by nature, as is the system capacity and the performance associated with each voice user. Thus, there may be occasions where not enough bandwidth is available to accommodate every active user according to target quality of service (“QOS”) levels. Additionally, even if bandwidth is available, there may be times when it is not possible to meet target or required QOS levels in transmitting voice or other data packets to a wireless access terminal, due to varying radio airlink conditions or the like.
In some instances, these problems may be compounded as a result of limitations in network electronic processing capacity. In particular, carrying out wireless packet data communications involves the ongoing electronic processing of large numbers of data packets. For this purpose, each element of network infrastructure (e.g., wireless units, base stations, RNC, MSC, etc.) will typically include one or more microprocessors or other electronic processing units. When network traffic load is heavy, processor resources may be overextended, e.g., in a particular leg/hop of the communication channel there may not be enough processing power to accommodate the data load according to required or target QOS levels. Additionally, with VoIP and multiple QOS applications such as best efforts data transfer and video telephony, there are complex bursty traffic patterns that result in large amplitude levels of loading surge and fluctuation. Loading surge and fluctuation may drive multiple processing devices into overload conditions. During such overload conditions, the processing units and communication buses connected thereto tend to have complex and/or erratic processor overload behaviors. These factors may result in flow drop and dropped packets, resulting in poor quality calls and unacceptable system performance.